tech A says that a Hall-effect sensor can be used in an electronic ignition system. Tech B says that an optical-type sensor can be used in an electronic ignition system. Who is correct

Both Tech A and Tech B are correct.

Explanation:

The Hall effect sen sensor are used to control displacements and rotations of various body components of the vehicles, engine vibrations, and the ignition system

The optical-type sensor converts rays of light into electronic signals. It measures the quantity physically of which the translates to a form that is understandable or readable by an instrument. An optical sensor is larger part of a system that integrates light sources, a device for measuring and the optical sensor, which therefore is usually connected to an electrical trigger.